Integrated Circuit card (IC card) is a new type of information tool after the appearance of the magnetic card. A micro-electronic chip is embedded in a card complied with ISO 7816 standard to form an IC card. At present, the IC card has been wildly used in many fields such as finance, traffic and social insurance, etc. For example, the traffic card for bus transportation is a kind of IC card.
IC card reader, which is called Interface Device (IFD) in the ISO international standard, is a bridge between the IC card and application system. Generally, the IC card communicates with the IFD by Radio Frequency (RE) technology. That is, the CPU of the IFD connects to and communicates with the IC card via an interface circuit. Thereby, the interface circuit is a very important part of the IC card reader. According to the actual application system, different IC card chips can be selected, such as the IC card with parallel communication, half duplex serial communication or I2C communication.
During the development of the present invention, the inventor finds at least the following weakness of the prior art:
When an IC card reader has multiple card holders, the host cannot identify such an IC card reader. As a result, the data communication and the instruction reception/transmission between the host and the card reader can not be realized.